Being a component of atmospheric air, carbon dioxide is widely distributed in nature and constantly exchanged between the atmosphere and ecosystems. It also serves as an indicator of the rate of processes taking place in the soil environment and reflects the rate of organic matter decomposition during industrial waste management and degraded land reclamation. Human activity may increase CO₂ emission to the atmosphere, thus contributing to its higher concentration in atmospheric air. CO₂ content of soil air is modified by a variety of factors, including temperature, humidity, porosity, root respiration, etc. CO₂ emitted to the atmosphere is the product of numerous chemical processes, primarily organic matter decomposition under aerobic and anaerobic conditions, and urea decomposition. This paper presents experimental results concerning CO₂ emission from light soil deposit in the form of overburden, before and after fertilization with sewage sludge. CO₂ emission was determined in a controlled environment chamber at a temperature of 10, 20 and 30°C and a constant water capacity of 60%. It was found that both higher temperatures and the addition of sludge increased CO₂ emission to the atmosphere. The observed relationships were confirmed by an analysis of variance, and correlations between the tested variables and CO₂ emission were determined.